Oct 20

Winterize your boat – and STAY ON THE WATER!


This is a check list for “Winterizing” a 2002 3470 Express by Cruisers Yachts.   The principles are the same for all boats, and all engine configurations, but for the record, this particular boat was powered by a pair of Volvo 8.1L “GXi” 375hp Inboard/Outboards with Volvo “Duo-Prop” out-drives.   This boat also stays in the water year-round, as the marina she is berthed in wouldn’t ice-over due to the implementation of under-water “bubblers”.  This document covers:

  • Treating the fuel
  • Visiting the pump out and heating up the engines and genny
  • Running the generator and heating it up
  • Changing the oil in the engines and generator
  • Winterizing the motors
  • Winterizing the generator
  • Winterize the plumbing

This is one in a continuing series of articles brought to you by COGA!   This Blog and Forum is absolutely free and the Forum (Click “Forum” above) is just loaded with interactive information, fun with fellow boaters, info for perspective buyers, give-aways, owners manuals, performance stats, and much, much more!!


1. Engines, Raw-Water Cooling, Power Steering


Four main tasks here – treat the fuel, “Fog”, change the oil, drain the blocks, manifolds, fuel cooler, and power-steering cooler/raw-water pump. Each engine type (Merc, Volvo, ??) will be slightly different, but they all work the same.   Check your manuals and adapt as needed.


Treat your fuel by follow the directions on a jug of “Stabil” or similar product.   This not only protects your expensive fuel, but also protects your fuel-injectors and carburetors from corrosion and deposits.  

Fogging is the process where you introduce fogging oil in to the engine by removing your spark/flame arrestors and spraying this oil in to your motor while it’s running.    Since you’ll be changing your oil, run the engines until they are nice and hot.


Blowing water out of your power-steering cooler and out-drive plumbing is accomplished by removing all possible water below the water-line level. I’ve had good luck attaching 2” ball valves (available at Home Depot) to the raw-water hose attached to the raw-water pumps, and BLOWING the water out with some good old fashioned hot-air…in my case, MY hot air. 

1.     Add Stabil to your fuel tanks – dose per treatment instructions, and run your engines to work the treatment through your fuel system.   I usually do this just prior to visiting the “honey sucker” to drain the holding tanks.  It gets your engines nice and warm (for the forthcoming oil change) and runs “Stabil” thru the injectors while you drain the nasties from the holding tank.


2.     While the engines are running, remove spark-arresters and “fog” each motor with your favorite stuff…I use “Merc’s Fogging Oil”.   Spray this gunk in, and pinch off your fuel-line so that the engine gets the oil and not fuel.   Keep spraying until the engine dies.   When you’re done, your pistons, rings, cylinders and intake are coated with this nasty smelling stuff.  

3.     Change your motor oil, filters and water-seps.  My Volvo’s have screw-fittings on the dip-sticks that allowing the use of a Jabsco oil-sucker ($150 from your favorite marine parts venue).


4.     When the oil has been removed, replace your oil filters.   A cleaver trick is to use a one gallon zip-lock bag around the filter so you don’t dribble oil all over yourself (and in to your bilge).   I also like to put the date and engine hours on the actual filter with a Sharpie, so someone else can tell at a glance when the last oil change was.  

5.     Drain your blocks and exhaust manifolds   Volvo’s have all the drains connected to one hose.  Exhaust manifolds have bronze cocks – open them.   Late-model Mercs have blue plugs, and the REALLY new ones seem to have a bicycle type pump, which sounds nifty.   Anyway, pull all the plugs and let the block and manifolds drains.


6.     Disconnect your raw-water pump inlet hose.   Volvo’s are mounted on the crank.   Like the water heater, there is a water INLET and a water OUTLET.    Volvo’s also have “riser” humps that keep the ocean from rushing in.    

7.     Clamp on ball-valves to the inlets, blow the water out until you hear bubbles under the transom.  Yes, you can do this with your mouth.  J   This blows the water level down below the water-line, and when you shut the ball-valves, keeps it there.   This also blows out the power-steering cooler on the Volvo’s.


8.     Tie wrap the ball valves up high, just in case.   

9.     Done!


2. Seacocks


It’s important to clear all the water out of your seacocks, which are nothing more than marine-grade ball-valves.   If a seacock breaks, you’re boat could sink.   That’s worse than this simple procedure.  A quick note:   If I were a salt-water guy, I’d replace every hose-clamp I could find…every year.   Use TWO Marine Grade stainless clamps for every connection below the water line.


1.     Close all your seacocks

2.     Disconnect all hoses from your seacocks

3.     Connect a temporary hose to each seacock

4.     Stick the hose in your mouth, and BLOW (nothing happens)

5.     While blowing, open the cock, and you’ll hear bubbles under your boat – this is good.   Don’t stop blowing!    Don’t worry – you won’t get your lips blown off from the water pressure.

6.     Keep blowing and close the cock.

7.     Done!




A generator is just an engine that has a mag attached to it….but it’s water cooled (raw-water in most cases).   You want to change the oil and flush the cooling system with “Pink Stuff”.  Hopefully you read the part about having a hot genny to facilitate engine oil removal. :-)


Since you’ve disconnected the raw-water seacock (above), the cooling for the genny is not there… You’re going to replace it (temporarily, of course) with “Pink Stuff”.  You don’t want to run the genny for more than a few seconds…but the water pump will suck up “Pink Stuff” and shoot it over the side.   This also winterizes the water-muffler of the genny, though it may be best to drain that.  On the 3470 (I/O) I wasn’t willing to crawl back there. Never had a problem.

1.     Clean out your sea strainer

2.     Fill the sea-strainer with “Pink Stuff”

3.     Attach a temporary hose to the intake side of the generator.

4.     Stick it in a bottle of “Pink Stuff” (or use a funnel).

5.     Start the genny, and have your mate watch the thru hull

6.     When “Pink Stuff” comes out, you’re done.

7.     Don’t forget to change the oil, filter, etc.  My recommendation is to attach a hose to the drain-barb and suck it out using your oil pump as above.

8.     Done! 


Water Heater

The hot water heater is nothing more than a big tank with an electric element in it to heat the water.   There is a drain, a cold-water INPUT and a hot water OUTPUT.   Later model Cruisers Yachts use “Quick Connects” to attach the lines to the heater unit. 


Most RV places sell Water Heater By-Pass kits.   If you don’t have one, you should consider the small investment (~$24).   This basically ties the cold and hot system tubes together and by-passes the whole hot-water heater.   The by-pass installs at the inlet/outlet of the heater and uses diverters to “cross-over”.   You want to drain every drop from the heater, but it is recommended that you NOT waste 6 gallons of “Pink Stuff” to fill the heater.

1.     Obtain/Install a Water Heater By-Pass Kit OR connect the cold water and hot water lines together and ensure the connection will hold pressure in the water system. 

Note:  If you don’t connect these hoses and bypass the water heater, you should fill your water heater with 6+ gallons of “Pink Stuff”.   You’ll never get all the “Pink Stuff” (or the taste) out of your system, so don’t do it.  As an aside, “Pink Stuff” is based on cooking oil (so I’m told) and is NOT poisonous, but it looks and smells pretty gross.


2.     Turn off the power to the water heater.  Mark the break, so you don’t turn it on when the heater is empty, which will zap the heating element.  I have some little tags and use Christmas tree ornament hooks to hang from each breaker that shows that the circuit is closed for the winter.  Sorry.  I’m anal.

3.     Drain the water heater in to the bilge and leave the drain valve open


Fresh Water System (Pump and Fixtures)

Overall, this procedure allows you to pump fresh water out of your water system and replace it with “Pink Stuff” utilizing the fresh water pump to replace fresh water with “Pink Stuff”.    Any fresh water left in the lines, pump, or fixtures will freeze and potentially crack/break your system.   As pressure must be maintained for the system to work (and provide running water), this is bad news…particularly when Mr. Murphy lives on boats, and you know the line that breaks will be completely inaccessible.

1.     Drain all the water from your fresh-water tank and shut the pump off (fresh water breaker)

2.     Pull the seat cushions from the aft cabin to allow access to the pump and filter.

3.     Disassemble the feed from the water tank to the pump (under port-side seat)

4.     Clean out the water filter there, and make sure it’s dry

5.     Attach a length of hose to the intake of the pump (a ½” NPT female barbed fitting with plastic hose works well and screws right on to the pump).

6.     Stick the hose in to a jug of “Pink Stuff”.   A funnel is also helpful, which allows gravity to assist in priming the pump.

7.     Get your mate to watch and have a few of extra gallons opened and ready. 

8.     Turn on the pump and ensure the supply of “Pink Stuff” is sufficient to re-pressurize the system and the pump kicks off. 

Note:  This may take up to three gallons, so be ready to keep feeding the thirsty pump!


9.     Start with the shower (furthest away from pump) and run each fixture until “Pink Stuff” comes out.   Each time you run a fixture, more “Pink Stuff” will be ingested in to the system.   Keep feeding the system as to not introduce air.

Note:  Your mate will be swapping bottles of “Pink Stuff” at a high rate of speed!

10.  Don’t forget fresh-water wash-downs (we didn’t do fresh-water washdowns in Colorado, but we did do RAW water – see below).  Cockpit wet-bar, and anything that is fed from the fresh-water system.

11.  Once you’ve run every fresh-water fixture in the boat, the system is loaded with “Pink Stuff”, and won’t freeze.

12.  Almost done!  Leave the “Pink Stuff” connected!


1.     You did visit the pump out and empty your holding tank right?…Of course, you’ve already DONE that prior to winterizing your engines, right?  Rinse it out several times with a garden hose and get as much goop out as possible.  Suck it dry!

2.     With the “Pink Stuff” still hooked up to the fresh water system, flush the head a few times until “Pink Stuff” flows.   It’s actually GOOD to flush the “Pink Stuff” – it lubricates the duck valves, vacuum pump, macerator and all other internal components.   And of course, keeps things from freezing.

3.     My head has a ball valve for the water intake.   To keep from continually using the “Pink Stuff” up, close this valve. 

4.     Leave some “Pink Stuff” in the bowl

Note:  In the winter, you can (in a pinch) use the head.   Just pour in the “Pink Stuff”, do your business, and flush.  Do NOT turn on the fresh water system or attempt to “add water” by opening the head bypass valve.  Emergencies only!

Air Conditioning/Heating


Your AC/Heat has a raw-water pump too.   Since you’ve already blown the water out of your seacock, you’re going to follow a similar procedure to pump “Pink Stuff” thru the AC unit until it goes overboard.  AC equipment (Seacock, Raw-Water Pump, etc) is under the floor at the bottom of the Companion Way ladder.

1.     Clean out your sea strainer and drain all water (7/16wrench on the bottom), and blow the water out of the Seacock as described herein

2.     Attach a temporary hose (7/8th ID) to the inlet side of the AC with a funnel on the end

3.     Fill with pink stuff

4.     Turn on the AC and have your mate watch the thru hull and be ready to pour more pink stuff

5.     You’ll hear the water pump turn on – it’s right there.

6.     When “Pink Stuff” comes out the side of the boat, you’re done. 

Note:    We tend to visit the boat all winter and run the heat year-round.   We’ve got this heater-winterization thing down to a 2 minute drill.  When you’re done, make sure the system is ready to run.   When you come down in January and are freezing to death, open the cock and fire up the heat.   Obviously re-run this procedure each time you ingest water in to the system.




  1. While you were working on your AC, did you clean out your shower sump pump?  It’s a nasty job, but you’ve got do it.   During the actual boating season, pour nice smelling Mr. Clean down the drain of the shower which will clean out the hoses, and fill the sump.   This will keep your boat from getting really, REALLY smelly from rotting hair balls and soap-scum.  In the winter, fill it up the sump with “Pink Stuff” and trigger the pump until “Pink Stuff” squirts out the side (but clean the sump up first).


  1. Pour “Pink Stuff” in your drains (clean them out too – as above)


  1. Clean your bilge(s) and dry them completely.   A clean bilge is a happy bilge.  A wet/dry vac is VERY handy.  My favorite is a little 2 gallon wet vac my admiral got me for Xmas a few years back.   I keep it aboard for all my watery issues.


  1. Wash-n-wax the whole boat – either in the winter or spring (or both).


  1. Remove anything that might collect mold, mildew, or other stinky stuff


  1. Did you tag circuit breakers for things like Fresh Water, Head, Macerator and things that you might turn on that are now loaded with “Pink Stuff”?


  1. As mentioned throughout this document, keep some pink stuff handy.  You can use your boat all winter long if you are careful with the water system.



  1. A couple of cases of Pink Stuff.   I find that 12 one gallon bottles gets me winterized and leaves enough to re-winterize the heat and flush for those emergencies.
  2. StaBil
  3. A good set of combination wrenches and screw drivers
  4. An Oil Sucker – Recommend the higher-priced Jabsco unit.
  5. Oil Filters.   Chevy blocks almost all use FRAM PH30’s, but read your warranty and make sure you won’t void it by using a third party.  Same with oils. Grab a filter for your genny as well.  
  6. A couple of cases of motor oil
  7. The Volvo 8.1L GXi’s take 9 quarts EACH
  8. The Volve 5.7L GSi takes 5.5 quarts
  9. The Generator takes 1.44 quarts
  10. PVC ball valves to plug engine raw water intake hoses
  11. A fine selection of rubber and/or plastic hose is handy – 1/2” 3/4” and 7/8” will probably fill the need.
  12. A couple of funnels!
  13. Bring jugs for used oils and such (empty pink-stuff jugs work too!).  Drop the oil at the local auto parts store.
  14. Ziplocs for nasty oil and gas filters
  15. Fogging oil
  16. WD-40 (or liquid wrench, or??)
  17. Tons of rags and cleaning supplies
  18. Tags and a supply of sharpies for labeling winterized systems
  19. Zip Ties

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